A project to develop the complete immunophenotype of memory B cell has been initiated. This is being done evaluating normal subjects and patients with a number of immune disorders. In addition, the immunophenotypic data is being compared with Ig gene recombination results generated in Dr. P. Lipskys laboratory (NIAMS). These investigations have established that CD27 expression is altered in CGD and this is a direct product of the defective oxidase activity as reflected by the link between CD27 expression and the proportion of normal cells in X-linked carriers. In addition, CD27 expression is markedly diminished in ALPS primarily related to protein cleavage from the cell surface. The actual link between CD27 expression and B cell memory status as well as mechanisms that control CD27 expression on B cells is currently under investigation based on the findings in CGD and ALPS.